A transistor is used in an amplifier circuit in common emitter...

${\beta}_{AC} = \dfrac{\Delta{i}_{C}}{\Delta{i}_{B}} = \dfrac{10 \times {10}^{- 3}}{100 \times {10}^{- 6}} = 100$

Power gain,${A}_{P} = \dfrac{∆ {{i}_{C}}^{2}{R}_{out}}{∆ {{i}_{B}}^{2}{R}_{in}} = {\beta}_{AC}^{2}\dfrac{{R}_{out}}{{R}_{in}} = {\left(100\right)}^{2} \times \dfrac{2 \times {10}^{3}}{{10}^{3}} = 2 \times {10}^{4}$

Therefore, $x = 2$